It is unclear how many people will receive the cards, designed to help people identify if cannabis is being grown near their homes, but it is understood Essex Police have been given a quantity to distribute.

Uttlesford’s Neighbourhood Watch co-ordinator, Alan Johnson, said the scratch and sniff cards were a national initiative launched by Crimestoppers.

“The aim is to help the public identify any local cannabis growing because the smell on the card replicates what they should be looking out for,” he said.

“In Uttlesford, cannabis farms are more likely to be in remote farm buildings or small industrial units, and in that respect the rural nature of the district is what can be attractive to people growing cannabis.”

It follows the force’s announcement that it has launched an operation to target criminal gangs travelling into the area from outside the county.

The dedicated team has been put together to bring down dealers who have been selling illegal drugs on the streets and in properties in north Essex.

Detectives will work closely with uniformed officers and partner agencies in major towns and cities across the Braintree, Uttlesford, Colchester, Tendring, Chelmsford and Maldon districts.

The operation was launched after intelligence indicated that criminals were believed to be generating revenue through the sale of drugs of more than £4,000 a day from each major town in the area.

Chief Supt Carl O’Malley, who set up the team, said: “The aim of the operation is not only to disrupt the supply of illegal drugs to north Essex but also to tackle the associated violence that these gangs can bring.

“Essex is generally a very safe place, especially for law-abiding members of the public, but we do know that violence between rivals involved in drug dealing is happening.

“Their numbers are not large but no-one in Essex should have to put up with this type of behaviour in their neighbourhoods and I want to tackle the problem head on.

“I would urge members of our community to come forward and tell us about what they either know or suspect is happening on their streets.”

Anyone with information about drug dealing or the gangs 101 or ring Crimestoppers anonymously on 0800 555 111.